Tubing anchor with slip-releasing mechanism



March 25,1958 0. B. REYNOLDS TUBING ANCHOR WITH SLIP -RELEASING MECHANISM Filed June 6, 1955 IN VEN TOR.

0. B. REYNOLDS "mm 24 v A T TORNEVS I 4 Patented Mar. 25, 1958 TUBING ANCHISR WITH SLlP-RELEASING ECHANISM Orvel B. Reynolds, Bartlesville, kla., assignor to Phillips Petroleum Company, a corporation of Delaware Application June 6, 1955, Serial No. 513,523 I 6 Claims. (Cl. 166-212) This invention relates to a well tubing anchor having slip-releasing mechanism. A specific aspect of the invention pertains to automatic hydraulic slip-releasing means in a tubing anchor.

Although a packer generally is, not used in a pumping well, as it is preferred to remove gas through the annulus around the tubing, usually it is desirable to provide a downhole support for the tubing. The operation of a pump at the bottom of a long tubing supported only at the top causes vibration, failure due to fatigue, and loss of power. .If, as is often the case, the pumpis operated by a string of sucker rods excessive wear of the sucker rod boxes and/or the tubing string can occur due to the sucker rod string rubbing against the inner wall of the' tubing. While someimprovement is effected by .p-artly supporting the tubing at the bottom of the well, it has.

been found better to use an anchor which permits the tubing to be placed in tension, thus preventing spiraling and bending of the tubing due to compression.

ing the tension in the tubing, or the slips are very difiicult or impossible to release when it becomes necessary to pull the tubing, thus causing an expensive fishing job.-

My invention comprises an improved tubing anchor which allows the slips to be set tightly against the wall of the easing but provides positive slip-releasing means to facilitate removal of the tubing and tubing anchor.

Ihe principal object-of'the invention is to provide a, tubing anchor for a string of well tubing within awell casing having releasing means. Another object is to provide a positive slip-releasing means for a well tubing having an automatic hydraulic slip-releasing deviceoperable with fluid pressure in the tubing. It is also an object of the-invention to facilitate removal of tubing anchors from wells by providing positive releasing means for the slips in the anchors. Other objects of the invention will become apparent upon consideration of the accompanying disclosure.

.As illustrated in the schematic drawing which is an elevation in quarter section, the tubing anchor of my invention comprises a mandrel 10, a housing 20, friction blocks 30, and slips- 49;. Mandrel 10 is provided with threads 11 for attachmentwith the tubing string 18, a tapered or conical projection 12, an annular projection 13ycontaining1 Q ring seal 14; and' perforations or conduits =15; Ring 13 is retnovably attached or fixed to mandrel ltip Lug lo -is attached to mandrel 10 by threads;

17. A continuous passageway 19 extends through the tubing string to provide for flow of oil.

Housing 20 is provided with openings 21 for friction blocks 30, openings 22 for slips 4t), annular projection 23 containing 0 ring seal 24, J-slot 25, annular projection 26 containing 0 ring seal 27, and threads 28 for attachment of the lower portion of the tubing string be low the anchor. Housing 20 is constructed in sections threaded at 42 and 43 to facilitate assembling.

The invention comprises an open tubular body constructed of a core section or mandrel surrounded by an outer section or housing, these sections being slidably and rotatably connected and there being means on one section for holding it in fixed position to permit axial and rotational movement of the other section. Slips are psitioned in axial slidable relation with the core section,

and are urged axially thereof along inclined planes to set and release same by movement of the outer section. A hydraulic releasing means for the slips comprises an annular hydraulic expansion chamber formed between the inner and outer sections and bounded at the ends of the annulus by ring members, one extending inwardly from the outer section and the other outwardly from the inner section, thereby providing a chamber of variable axial dimension as axial movement of the sections with respect to each other is effected. Perforations or conduits from the axial passageway of the anchor to the expansion chamber permits automatic expansion of the chamber and axial movement of the sections to effect release of the slips.

Friction blocks 30 are held in place in openings 21 and housing 20 by screws 31 and are urged outwardly by springs 32. Slips slidably engage conical projection 12 and move outward in openings 22 as mandrel 10 moves upward relative to, housing 20 and the edges of openings 22 prevent upward movement of slips anchor. A further object is'to provide a tubing anchor 40. A split ring 41, preferably made of spring steel, fits in groovesinthe bases of slips 40 as shown and assures uniform movement of the slips both axially and radially of the mandrel. Lug 16 cooperates with -J-slot 25 to prevent axial movement of mandrel 10 relative to houshydraulic expansion chamber when slips 40 are set against the casing and ring member 23 is in a position below that shown in the drawing. Sucker rod 34 extends axially through the tubing string to' a pump (not shown) and passes through the anchor where the pump is below the anchor. The sucker rod also connects with lifting means (not shown) at the well head. Usually the tubing anchor of theinvention utilzes th friction blocks and slips in sets of three spaced uniformly around the circumference of the hollow body in which r they are positioned. However, two or more units may comprise a set, the invention being not limited to any specific number.

In operation, as the tubing string and attached anchor are lowered into the well, mandrel 10, housing 20, and

their associated parts are in the position illustrated, lug 16 in the shorter leg of J-slot 25 preventing axial movement of mandrel 10 relative to housing 20; Friction blocks 30 engage the inner wall of the casing.- When-the desired setting depth is reached the upper portion of the tubing string and mandrel 10 are rotated to the right;

Friction blocks 30 prevent rotation-of housing 20 and the lowerportion of the tubing string belowlh? anchor," thugpermitting lug 16 to enter the longer leg of J-slot permit placing the tubing string under tension.

When it becomes necessary to pull the tubing string from the well the tension in the tubing is released and the entire string and mandrel lil 'are lowered-slightly.

If the slips release their 'grip on'the-casing wall easily,

further lowering of mandrel-10 pulls slips 40 back into the retracted position and a slight turn to the left reengages lug 16 in the shorter leg offJ-s lot 25' and the entire assembly can be lifted from the well. However, it often happens that slips 40 cannot easily be released but remain-in the-extended position as. the entire assembly is lowered, thus'preventing i e-engagement oflug 1-6 in the shorter leg of J-slot 25' and the'tool and attachedtubing cannot be removed from the well. .When this occurs, fluid pressure applied within the tubing string also is applied through perforations 15 to annularchamber-45. A standing-valve comprising ball 47 and seat 48 in the tubing below the anchor prevents loss of pressure to the casing annulus. The standing valve may be similar to that of U. S. Patent 1,941,813 to Nixon et al. or that shown in Petroleum Production by Wilbur F. Cloud, University of Oklahoma Press, Norman, Oklahoma. As

'the pressure in chamber 45 increases a force is applied 7 on projections 23' and 13 to move mandrel downward relative to housing 20, thus retracting'slips 40 and allowinglug 16 to be re-engaged with J-slot 25 as described above. a

'It will be recognized that, in normal operation the pressure within the tubing string is greater than the pressure in the casing annulus due to the head of liquid in the tubing string and it is not necessary to provide additional pressure within the tubing string'to release slips 40. Hence, release of slips 40' will normally take place automatically when the string is lowered and tensionis relieved. If, however, slips 40 do not release automatically, additional pressure may be applied within the tubing string as explained above to apply a positive releasing force to the slips. 7

Certain modifications of the invention will become apparent to those skilled in the art and the illustrative detailsv disclosed are not to be construed as imposing unnecessary limitations on the invention. a

I claim: V 7 1. A tubing anchor for anchoring a tubing to a surrounding well casing comprising a tubular body having means for interposing same in a tubing string, said body comprising inner and outer concentric tubular members threaded on opposite ends for attaching in said tubing longitudinally and rotatable therewith and having a threaded lower end for attaching to a pipe joint; longi wardly by longitudinal movement of said mandrel in one direction relative to said housing; friction blocks extending outwardly from said housingadapted to engage a surrounding well casing andprevent rotation of said housing; hydraulic operating means for releasing the out- ,ward force on. said slips, comprising .a closed annular "space between said mandrel and said housing defined by string and providing an annular compression chaming said inner tubular member, a second ring in said chamber below said first ring secured and sealed to said inner tubular member and slidably engaging said outer tubular member, and conduit means connecting the passage in said inner tubular member with said chamberan upper inwardly extending ring member on said housing forming a slidable seal with said mandrel and a lower outwardly extending ring member on said mandrel forming a slidable seal with said housing whereby hydraulic pressure exerted 'between'said ring members when said slips are'set forces said'housing along said mandrel in the opposite direction so as to'release' the force on said slips, and at least one conduit from the tubular opening in said mandrel to said annular space.

3.A tubing anchor comprising an open tubular mandrel threaded at the, upper end for attaching to a tubing string; a housing around said mandrel terminating in a threaded lower end for attaching. to a. pipe collar; longitudinally inclined surfaces'on an intermediate section of said mandrel flared outwardly and downwardly; radial openings in said housing opposite said inclined surfaces; a slip, in each said opening having an inner inclined surfaceadapted to engage aforesaid inclined surface and urge; saidslip outwardly when 'said mandrel is pulled upwardly relative to said'housing; a J-slot-and-lug attach ment between said housing and said mandrel; outwardly expanding friction blocks on said housing adapted to engage a surrounding casing so as to hold said housing sta- I tionary for manipulation of said mandrel and said lug in said J-slot and engaging of said slips with a surrounding casing meanstor urging said slips inwardly; hydraulic means for releasing the outward force on said slips comprising a closed annular expansion chamber around said mandrel between an inwardly extending shoulder on a lowersection of, said housing and an outwardly extending shoulder on an upper section of said mandrel; afirst ring member extending inwardly into said chamber from said housing adjacent the shoulder on said mandrel, said first ringmember being fixedton said, housing' and forming a slidable seal with said mandrel; a second ring member extending outwardly into 'said chamber from said mandrel intermediate said first ring member and the V shoulder on said housing, said second ring member being 2. A tubing anchor comprising an open tubular mandrel having a threaded upper end for-attaching to a stringof-tubing; a housing around said mandrel, movable fixed on saidv mandrel forming a slidable seal with said housing; and conduit means. connecting the passage in said tubular'mandrel with said hydraulic expansion chamber.

4. The anchor of claim 'lin a tubing string having a standing-valve in said string below said anchor blocking References, Citedin the tile of this patent UNITED STATES PATENTS,

'Grinnel etal. Dec. 4; 1934 1,983,287 2,275,935 Baker Mar. 10, 1942 2,319,493

Drinkard ..-May 18, 1943 

